Problem: Solve for $t$ : $15 = t - 17$
Solution: Add $17$ to both sides: $ \begin{eqnarray} \\ \hphantom{15 {+ 17}} &\hphantom{=}& \hphantom{t} \\ 15 &=& t - 17 \\ \\ {+17} && {+17} \\ \end{eqnarray} $ $ \begin{eqnarray} \\ 15 {+ 17} &=& t \\ \end{eqnarray} $ Simplify. $ t = 32$